1. Field of the Invention
The present invention relates to bed heating systems and is useful in particular, but not exclusively, for heating beds and floors in domestic and hospital situations.
2. Description of the Related Art
Various bed heating systems have previously been proposed, but most of such prior systems employ electrical heating elements embedded in a mattress or a blanket, which gives rise to various problems.
For example, when a person lies on such a prior art bed, the body of that person is subjected to electrical noise from the heater element. Also, the heater element consumes a large quantity of electrical power.
It is accordingly an object of the present invention to provide a novel and improved heating system which avoids subjecting users to electrical noise and which operates so efficiently as to require little electrical power.
According to the present invention, there is provided a heating system comprising a tube extending in an array which has a water inlet portion, a water outlet portion and a sinuous intermediate portion between the water inlet and outlet portions. The heating system has a longitudinal inner area, extending centrally along the tube array, and a pair of longitudinal outer areas extending at opposite sides of the inner area. The intermediate portion of the tube has innermost runs distributed over the central area and connected directly to the inlet portion and to one another and outermost runs distributed over the outer areas and connected directly to the water outlet portion and to one another. A pump has an outlet connected through a water heater to the water inlet portion and an inlet connected to a water reservoir for supplying heated water to the tube.
With this arrangement, the newly heated water, arriving at the tube from the water heater, flows firstly through the longitudinal inner area, which is where a person using the tube array is usually positioned. From this inner area, the water, as it becomes cooler, flows along the outer areas of the array. Thus, the heat supplied to the tube by the water is mostly concentrated in the inner area, where it is of the greatest use.
In a preferred embodiment of the invention, the water reservoir comprises a water tank having a tank inlet connected to the water outlet portion of the tube, a tank outlet communicating with the interior of the tank and connected to the pump inlet and a water duct connected to the tank inlet, the water duct having a duct outlet arranged to discharge directly into the tank outlet.
By this means, water passing from the tube into the tank, which will contain residual heat from its previous heating by the water heater before it entered the tube, passes directly to the tank outlet and, thus, back to the water pump so that the residual heat in this water is, to at least a substantial extent, retained in the water and not lost to any cooler supply of water remaining in the tank.
The water heater is preferably a cylindrical water heater contained in a cylindrical housing, which defines a cylindrical water heating passage between the housing and the water heater, the pump having an outlet connected through the water heating passage to the water inlet portion of the tube. Consequently, the water to be heated, as it passes through the cylindrical water heating passage, is brought into close proximity with the water heater, thus promoting efficient heating of this water.
The tube array may be provided in a mattress pad or may be installed in a floor or other sleeping area without a mattress pad.